1. Field of the Invention
The present invention relates to a photoelectric conversion device module including a plurality of photoelectric conversion devices on one substrate and a manufacturing method of the photoelectric conversion device module.
2. Description of the Related Art
The progress of global warming is serious and there is a demand for clean energy. Photoelectric conversion devices typified by solar cells are thought to be typical of the next generation energy, and recent research and development has been extremely actively made and the market for solar cells are rapidly expanding.
Solar light which is an energy source of a photoelectric conversion device is inexhaustible, available for free, has a possibility to contribute to reduction of carbon-dioxide emissions, and thus is very attractive. However, such a photoelectric conversion device using solar light cannot achieve sufficient efficiency of photoelectric conversion and has a dependency on daylight hours. Thus, the commercial cost of such devices is not lowered, which hinders widespread utilization. Thus, high efficiency and low cost of such photoelectric devices are demanded.
Such photoelectric conversion devices can be formed using a silicon-based material or a compound-based material, and silicon-based solar cells such as bulk type crystal silicon solar cells and thin film type silicon solar cells are mainly commercialized. Such bulk type single-crystal silicon solar cells can achieve high efficiency but are disadvantageous in the consumption amount of resources and manufacturing cost because they are formed from single-crystal silicon substrates. In addition, such bulk type single-crystal silicon solar cells are difficult to be enlarged, because they depend on the size of a single-crystal silicon substrate. On the other hand, thin film type silicon solar cells are formed using silicon thin films formed by a CVD method or the like and thus can achieve resource saving, enlargement in area and reduction of manufacturing cost, but cannot achieve sufficient photoelectric conversion efficiency.
In order to keep high photoelectric efficiency and achieve low cost and resource saving, a method for manufacturing a solar cell is proposed in which hydrogen ions are implanted into a crystalline semiconductor and the crystalline semiconductor is cut by heat treatment to obtain a crystalline semiconductor layer (for example, see Patent Document 1). After a crystalline semiconductor in which ions of a predetermined element are implanted in a layered manner is attached to a surface of electrode-forming paste applied over a substrate provided with an insulating layer, heat treatment is performed at 300° C. to 500° C. to bond the crystalline semiconductor to an electrode. Next, by heat treatment at 500° C. to 700° C., voids distributed in a layered manner are formed in a region of the predetermined element implanted into the crystalline semiconductor, and further, the crystalline semiconductor is divided at the voids by heat distortion. Accordingly, a crystalline semiconductor layer over the electrode is obtained.
Further, in order to efficiently utilize solar light having a wide spectrum, solar cells having a multilayer unit cell structure have been researched for a long time. For example, Patent Document 2 proposes a stack type solar cell with different type unit cells in which an amorphous unit cell is stacked on a crystalline unit cell.
Further, in order to utilize photovoltaic power generation for housing or commercial use, electromotive force generated by a single photoelectric conversion device is not sufficient, and thus there is a need to connect a plurality of photoelectric generation devices (photoelectric conversion cells) in series or in parallel to make a module. For example, a photoelectric conversion device is known, in which a multilayered body in which a photoelectric conversion unit including hydrogenated amorphous silicon and a photoelectric conversion unit including crystalline silicon are stacked is formed on a translucent substrate with an electrode layer therebetween and power generating regions of the multilayered body are sectioned by trenches and these are connected in series (e.g., Patent Document 3).
[Patent Document 1] Japanese Published Patent Application No. H10-335683
[Patent Document 2] Japanese Published Patent Application No. S59-124772
[Patent Document 3] Japanese Published Patent Application No. 2005-038907